Csail
N/A
What are regarded as the best jump leads on the market?
jump leads
- Thread starter Csail
- Start date
breezer5012
Well-Known Member
One's that reach from boat A to boat B
/forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif
/forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif
sarabande
Well-Known Member
Lorry ones from your farm supplies, or commercial motor factor place.
Hint. Make sure the jaws have no exposed teeth, i.e are well covered in plastic insulation, or you could accidently turn them into welding rods.
Also, tape the leads together with duct tape, leaving enough lead (about 18 inches) at each end for the clips to reach the terminals. This prevents the leads tying themselves in knots, tripping people up, and generally getting caught up in mechanisms.
Also, learn the correct sequence for putting them on between the donor and recipient batteries. Or mark the clips in indelible ink "First", "Second", etc, in case anyone who doesn't appreciate spontaneous fireworks has a go at connecting up.
Sorry, egg-sucking time. Apologies.
Hint. Make sure the jaws have no exposed teeth, i.e are well covered in plastic insulation, or you could accidently turn them into welding rods.
Also, tape the leads together with duct tape, leaving enough lead (about 18 inches) at each end for the clips to reach the terminals. This prevents the leads tying themselves in knots, tripping people up, and generally getting caught up in mechanisms.
Also, learn the correct sequence for putting them on between the donor and recipient batteries. Or mark the clips in indelible ink "First", "Second", etc, in case anyone who doesn't appreciate spontaneous fireworks has a go at connecting up.
Sorry, egg-sucking time. Apologies.
doris
Well-Known Member
Correct sequence
Yes I know I really should know this but since the earth situation is different to a car, what is the correct sequence for jump leads on boats?? Sorry to be the thick one of the forum.
Yes I know I really should know this but since the earth situation is different to a car, what is the correct sequence for jump leads on boats?? Sorry to be the thick one of the forum.
brianrunyard
Well-Known Member
Best answer I've seen today
kengill
Well-Known Member
As it's for a yacht you need to make sure the cables are ok if they dip into the water and have a sufficiently high tensile strength to withstand the strains and stresses of being alternately pulled and crushed. So you might want to use something like 250sqCu/11.7mmXLPE insulated/ 1.6mm steel sheathing/ 3mm pvc sheathing in case you have a high current load and to prevent the cable getting pinched between the boats. The vertical access hatches leading down to the battery compartments should have appropriate securing clamps to prevent the cables becoming inadvertantly unattached. It only weighs about a ton or so, so it should be useable in any decent sized yacht and you could just let the crew get on with it while you continue your game of snooker on the 5 axis stabilised table in the games cabin.
Minimum bend radius of this sort of stuff is about 2 to 3 metres so you'll need about 16 to 20 metres plus of course the heavy duty crocodile clips to connect to the battery terminals. You can easily store the cable when not in use by hoisting it up the mast to keep it straight or by having a housing built for it in the deckhead.
/forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif
There again you could just use flexible welding cable of say 80 mm sq, which is what I use for my windlass wiring, this comes with both cores sheathed together.
Minimum bend radius of this sort of stuff is about 2 to 3 metres so you'll need about 16 to 20 metres plus of course the heavy duty crocodile clips to connect to the battery terminals. You can easily store the cable when not in use by hoisting it up the mast to keep it straight or by having a housing built for it in the deckhead.
/forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gifThere again you could just use flexible welding cable of say 80 mm sq, which is what I use for my windlass wiring, this comes with both cores sheathed together.
bdsweeting
Well-Known Member
Normal correct sequence of connecting jump leads is...
Assuming a negative earth system
Donor battery positive then connect to dead battery positive
Donor battery negative then connect to a good earth on the engine block of the dead battery boat.
(This will ensure that there are no sparks near the dead battery when you disconnect)
Assuming a negative earth system
Donor battery positive then connect to dead battery positive
Donor battery negative then connect to a good earth on the engine block of the dead battery boat.
(This will ensure that there are no sparks near the dead battery when you disconnect)
sarabande
Well-Known Member
Can I followup MEP's words ? It is important to use an earth on the "dead" vehicle which is away from from the negative terminal at the battery. In case the battery is /has been offgassing hydrogen.
Given the correct stochiometric (hydrogen - oxygen ration) in the air, you only need a very small spark (and sometimes, none at all !) for a very big bang.
may all your connections be positive first...
Given the correct stochiometric (hydrogen - oxygen ration) in the air, you only need a very small spark (and sometimes, none at all !) for a very big bang.
may all your connections be positive first...
William_H
Well-Known Member
high csail There are jump leads available which actually have a power converter built in whic will take 12 volts from one battery and increase to 14 volts to charge another battery. Known as electronic jump leads they carry only of the order of 10 amps to you flat battery so take some time to put any charge into the flat one. You can a similar effect with just low current wires from a donor battery on charge from an engine but at a lesser current rate.
Now this proicess only works if your battery is discharged but still good. You willeventually have the problem where the flat battery is actually old (failed) so that any amount of charging will not start your engine. It is at that time that you need fat jumper leads that will suply hundreds of amps to either assist or substitute for your dead battery to crank the engine. So ultimately you are best off with as big and as long leads as you can find.
The boating answer of course is the second battery option. So you should not get inadvertent engine battery discharge and when the engine battery dies you can use the service battery as a substitute or assist. This can be done by switching or by physically changing the battery lead from one battery to the other or by connecting with a short jumper lead. Note the negative is usually permanently connected all batteries to the engine by a heavy cable. However if using a jumper lead be very carefull as there can be sparks on making the connection and it is not usually easy to do so at any where other than the battery terminal.
regarding using switching many people use both batteries to start as routine as this then charges both. This means that you are never made aware of the failure on one battery until infact both drop dead> (as they will eventually) olewill
Now this proicess only works if your battery is discharged but still good. You willeventually have the problem where the flat battery is actually old (failed) so that any amount of charging will not start your engine. It is at that time that you need fat jumper leads that will suply hundreds of amps to either assist or substitute for your dead battery to crank the engine. So ultimately you are best off with as big and as long leads as you can find.
The boating answer of course is the second battery option. So you should not get inadvertent engine battery discharge and when the engine battery dies you can use the service battery as a substitute or assist. This can be done by switching or by physically changing the battery lead from one battery to the other or by connecting with a short jumper lead. Note the negative is usually permanently connected all batteries to the engine by a heavy cable. However if using a jumper lead be very carefull as there can be sparks on making the connection and it is not usually easy to do so at any where other than the battery terminal.
regarding using switching many people use both batteries to start as routine as this then charges both. This means that you are never made aware of the failure on one battery until infact both drop dead> (as they will eventually) olewill
VicS
Well-Known Member
Sarabande and MEP are right. Recommendations regarding the sequence do vary but the most important points are that the <u>last connection, and first disconnection</u> should be on the vehicle/vessel with the dead battery and that it is away from the battery itself.
Hydrogen/air mixtures are explosive over a very wide range of compositions (from as little as 4% IIRC) and when batteries are involved oxygen will also have been produced in an equivalent amount to make matters worse, as Sarabande points out.
It is also a smart idea to start the engine on the assisting vehicle/ vessel first and allow that to charge the dead battery for a few minutes. Then the current draw via the jump leads is minimised and you do not end up with two vehicles/vessels with flat batteries and neither engine running.
Hydrogen/air mixtures are explosive over a very wide range of compositions (from as little as 4% IIRC) and when batteries are involved oxygen will also have been produced in an equivalent amount to make matters worse, as Sarabande points out.
It is also a smart idea to start the engine on the assisting vehicle/ vessel first and allow that to charge the dead battery for a few minutes. Then the current draw via the jump leads is minimised and you do not end up with two vehicles/vessels with flat batteries and neither engine running.
